Inject sound to a phone landline (electric boogaloo)

[Coolsuggies]

tl;dr: I want to put a fake dial tone .wav over a phone line to trick my Sega Dreamcast into dialing.

I'll try to keep this pretty straight forward. I know there are much easier ways to do what I'm trying to accomplish (get a Sega Dreamcast to play Quake 3 which doesn't support blind dialing), but I'm at where I'm at because this is what I wanted to do it this way. I chose not to not go the dreampi route because I have a working win98se with voltage line inducer that works on getting it on the Internet. My last hurdle is to trick the Dreamcast into dialing for quake 3 because it's stupid and doesn't support the blind dialing feature.

I want to know how I can take a 3.5mm phono cable (2 rings, stereo only no mic (I think)) and splice that into a 4 wire phone line so the Dreamcast 'hears' a dial tone.

 

[AnalogKid]

For a standard phone line, the phone signal is on the center two pins of an RJ-11 connector. In the cable, the wires are red and green.

Since you know nothing about the interface circuits for the modem and the Sega, start with a coupling transformer. Typically these are designed for an impedance ratio of 600:600 ohms. If you have an old/dead modem board, it probably has one you can salvage.

Do you have an audio file of a proper dial tone?

ak

 

[Externet]

To inject audio to a plain telco line which is 2 wire lines, not four; you need a plain audio output transformer; like 8 Ohm to 1K Ohm.

( Like RadioShack 273-1380 )




Connect the secondary 8 Ohm winding in series to only ONE of the telco wires pair. Inject audio to the 1K Ohm primary winding. Adjust its level to produce less than 0dBm at the telco line or as desired. Same to extract audio from a telco line. The telephone must be off-hook.

R------------------------------------------------------------R
T--------------------------uuu------------------------------T

'uuu' is the 8 Ohm primary of the transformer. 1K Ohm secondary not drawn.

 

[Delta Prime]

I'll try to keep this pretty straight forward

Here's a little snippet of the link below.
Not going to happen...
You better have a 56k modem for both your PC and Dreamcast for optimal connection speeds. PC 56k modems have a cap of 33.6kbps. Thus, your Dreamcast will only be able to download and upload at a max rate of 33.6kbps. Your PC should be around 400MHz with 128mb of ram. Too little ram will result in the PC juggling ram between applications and can result in connection errors.
There are a few different types of Modems that can be used with this process. Note: You must have a VOICE compatible modem!
Internal PCI modems - These modems are often software based modems. Meaning they require software to do some of the legwork. Because of this, there is not enough voltage available to move the data along the telephone cord to the Dreamcast. If you are using an Internal modem you will most likely have to build a Line Voltage Inducer.
External USB modems - These modems are a bit more expensive, but they should not require the use of a line voltage inducer.
Regardless of what modem you use, you will still need to use the "swap" trick for all games that do not support Blind Dial. The swap trick involves 2 phone cords, and the following steps:
Plug the phone cord to the wall, and run it to the Dreamcast plug the second phone cord
into your PC 56k modem, and have the other end waiting over near your dreamcast
Hit connect on the game/application you are trying to use, wait for about 5-8 seconds
unplug the wall cord from the back of the dreamcast, and quickly plug in the cord leading back to your PC 56k modem.

Dreamcast Online -

Your primary source for online gaming on the Dreamcast, GameCube, or Playstation 2.

dreamcast.onlineconsoles.com